Derrick



2 Sheets-Sheet 1. W. B. PLESS. DERRICK.

(No Model.)

No. 418,221. Patented Dec.31, 1889.

2 Sheets--Sheet 2.

(No Model.)

W. B. PLESS. DERRICK.

No. 418,221. Patented Dec. 31-, 1889.

WWW S/vwe/WboM /%Q%WU, 7'" $1M wwwwm 6 UNITED STATES PATENT OFFICEVILLIAM B. PLESS, OF STOCKTON, ASSIGN OR OF ONE-HALF SARGENT, OF SANJOAQUIN, CALIFORNIA.

TO ROSYVELL O.

or other motive power within the hull. Forwardly-extending jaws H areattached to the turn-table and embrace the boom J.

N N are the jaws of the dipper, which is of a clam-shell pattern. a andb are the handles, to which are attached lever-arms c, having eyes attheir outer ends. The handles a and b are pivoted at a working centerupon a shaft cl. The dipper is suspended by chains 6 o I, attachedthereto and to a pulley M, and by chains L, attached to the eyes of thearms A hoisting-chain K is attached at the outer ends of the boom J,

the pulley L, over a sheave lso over a sheave G in the -mast G, thenextendsdown ward inside of the at the bottom of is suitably connected tothe motive power within the hull. A chain K is 1 end of the boom J andpasses through the pulley I] and upward over the sheave J extendsreardownward over the sheaves G this specification.

My invention relates to that class of dredgers which are located upon afloating vessel, and the novelty will be fully understood from thefollowing description and claims, when taken in connection with theaccompanying Figure 1 is a side elevation of my completedredging-machine and its vessel. Fig. 2 is a section of the derrickthrough line X X of Fig. 1. F' enlarged sectional detail view of thederrick-mast and ball-joint. Fig. 4 is a detached plan view of thederrick, turntable, and its arms. may be slacked at once and the dippeilow- I A B represents the hull of the vessel, upon ered WVhen the ipperis upon the mud which bot wound, causing the aws are located theoperating devices and C is a cross-beam whose ends yond the hull of thevessel.

is the derrick-mast, which is hollow, and has at its lower end aball-joint composed of a ball G stepped in a socket F in the beam t thehead of the mast G, cured thereto, is a gudgeon E placed the eye E of abrace 0, to

extend befor another load.

hat I claim as new and of my invention 1s- 1. The combination,substantially as de scribed, of the hull A B, the hollow mast G,provided with the ball-joint F G at one end and the gudgeon E at theother, the turn-table I, provided with I p and of ends of which are at-Side braces TOO about the mast G, and by means of a rope b I 7 leadlllghe combination, substantially as de to the engine scribed, of the hull AB, the cross-beam C, the

sheave G! mast, an d in the mast the turn-table I, with ing-i'ope, thegudgeon E the bail-joint block E, engaging w supporting carrying thewith its eye E engagi G3 beneath the beam G, the mast G, the jaws ith ng With C, the sheave provided with H,and operatat the top of the F G2 atits foot, the

the gndgeon E and braces, the brace 0, the gudg'eon E and the attachedto boom the foot of the mast G.

J, attached to the ja WS J,

In testimony whereof I affix m y signature in presence of two Vitnesses:

JOSHUA witnesses.

WILLIAM B. PLESS.

B. WEBSTER,

MAY HOLT.

